Method of stretching and attaching an insulator to a supporting spring structure



Feb. 23, 1965 R. P. DOERER 3,170,221

METHOD OF STRETCHING AND ATTACHING AN INSULATOR TO A SUPPORTING SPRING STRUCTURE Original Filed Nov. 13, 1961 2 Sheets-Sheet 1 INVENTOR.

A T'TOR/VZYJ uuu -luuuuuuuuuu 23, 1965 R. RDOERER 3,170,221

- METHOD OF STRETCHING AND ATTACHING AN INSULATOR TO A SUPPORTING SPRING STRUCTURE Original Filed Nov. 13, 1961 2 Sheets-Sheet 2 i- In! W I 0.." O

'- 0 0 0 0 4 I ll IE- 5 Wm J ZZZSL United States Patent This invention relates to a method of pre-stretching and attaching an insulator to'the supporting spring structure of an upholstered assembly, and is a division of my copendirig application Serial No. 151,771 filed November 13, 1961 which issued May 12, 1954, as United States Letters Patent 3,132,352.

One of the essentialobjects of the invention is to provide a method of pre-stretching an initially formed, flexible stretchable insulator to a length approximating the length of the supporting spring structure.

Another object is to provide a method of forming an insulator .for use between an underlying supporting spring structure and an overlying padding, comprising providing a stretchable resilient insulator which in its initial free state has a lengthwise dimension less than the minimum lengthwise dimension of the supporting structure, and longitudinally stretching the insulator beyond its elastic limit to a stablefree state condition of increased length in which the lengthwise dimension thereof approximates the lengthwise dimension of the supporting spring structure.

Another object is to provide a method of shaping an initially formed, elongated, flexible, extensible insulator to a configuration approximating the contour of the supporting spring structure, comprising gripping'opposed edge portions of the insulator, relatively moving the gripped edge portions away from each other to bodily stretch the insulator to a configuration approximating the contour of the supporting spring structure, and then releasing the gripped ends of the insulator.

Another object is to provide a method wherein the insulator is overstretched so that when released it will spring back to the contour of the supporting spring structure.

Other objects, advantages and novel details of construction of the invention will be made more apparent as this description proceeds, especially when considered in connection with the accompanying drawings, wherein:

FIGURE 1 is a perspective view of an upholstered assembly provided with an extensible insulator embodying my invention, and showing parts'broken away and'in section.

FIGURE 2 is a top plan view of the insulator, shown in its free state in conjunction with apparatus for stretching the insulator to aconfiguration conforming generally to the contour of the border frame of the supporting spring structure of an upholstered assembly, the ends of the border frame being shown in dotted lines and the ends of the insulator and clamps gripping the same also being shown in dotted lines in'the position they assume just prior to release of the ends of the insulator by the clamps after stretching.

FIGURE 3 is a sectional view taken on the line 3-3 of FIGURE 2.

FIGURE 4 is a top plan view of the pro-stretched insulator shown marginally secured to the border frame of the supporting spring structure.

FIGURES 5 to 11, inclusive, are sectional views taken respectively on the lines 5-5, 6-6, 7-7, 8-8, 99, 10-10 and 11-11 of FIGURE 4.

3,170,221 PatentedFelo. 23, 1965 FIGURE 12 is a plan view of an assembly composed of a pro-stretched insulator and a layer of padding bonded thereto in surface-to-surface relation, shown overlying I the border frame of the supporting spring structure before being secured thereto.

FIGURE 13 is a View similar to FIGURE 12 but shows the insulator and padding bonded thereto secured tothe border frame of the supporting spring structure.

FIGURE 14 is a sectional view taken on the line 1414 of FIGURE 13.

FIGURE 15 is a sectional view taken on the line 15-15 of FIGURE 13.

In the drawings, A is an elongated, rectangular, substantially horizontal, flexible, bodily stretchable, sheetlike insulator embodying my invention disposed between an overlying padding B for an exterior trim material C and an elongated underlying supporting'spring structure D of predetermined length of an upholstered assembly.

'As shown, the insulator A includes an elongated, substantially rectangular, extensible sheet 16 of flexible material, and separate elongated, laterally spaced, parallel stretchable resilient reinforcing strands 11 of uniform length threaded lengthwise through the sheet 10.

The sheet iii is formed with a longitudinal series of transverse pleats or undulations I2, and the reinforcing strands Ill are preferably in the form of helically coiled wires at right angles to the pleat. The strands 11 thread through the pleats 12 so that alternate pleats lie on opposite sides of the strands, as shown in FIGURE 5. In the initial free state of the insulator shown in FIGURE 2, the undulations or pleats 12 arerelatively deep and close together, substantially as shown in FIGURE 5, and the reinforcing strands are all of the same pitch, being suitably coiled and having a plurality of convolutions between successive undulations or pleats of the sheet. It will be understood that in some instances the pleats may extend longitudinally of the sheet and the strands may extend transversely of the sheet and may be threaded through the longitudinally extending pleats.

The insulator A also includes a pair of elongated anchorage portions 13, one along each end of and separate from the sheet 19. The reinforcing strands 11 are terminally provided at each end with return bent portions 14 which are clamped around the anchorage portions 13.

The supporting spring structure includes an elongated substantially horizontal border frame 18 of predetermined length, made to the desired configuration and area from a wire element or the like and having contoured ends 28 and 21. It will be noted that the rectangular insulator til has, in its initial free state shown in FIGURE 2, an overall length less than the minimum lengthwise dimension of the border frame, measured between the ends 2i) and 21 thereof, and a width substantially equal to that Prior to the application of the insulator to theborder frame '18 of the supporting spring structure, the insulator is stretched to a stable configuration approximating the contour of the border frame. The stretching apparatus is indicated generally at E in FIGURES 2 and 3 and comprises the two identical stretchers 22 and 23. Each stretcher has a base 24 and cam assemblies 25 and 25' supported thereon for sliding movement in the direction of the arrows 26. Each cam assembly includes an upper cam plate 27 and a lower cam plate 28 rigidly secured together by the upright posts 29. The cam assemblies 25 and 25 are reciprocated in the direction of the arrows 2.6 by the hydraulic devices 30. Each hydraulic device 3% includes a cylinder 31 fixed to the base 24 and a piston (not shown) reciprocable therein having a rod 32 extending therefrom and secured at its free end to the lower cam plate 28. In FIGURES 2 and 3, the cam assembly 25 of the left hand stretcher 22 is shown in its inner position extended toward stretcher 23 and the cam assembly 25' of the right hand stretcher 23 is shown in its outer position retracted away from stretcher 22. The cam assembly 25 can be retracted to an outer position corresponding to the position of cam assembly 25' shown in FIGURES 2 and 3, and the cam assembly 25 can be extended to an inner position corresponding to the position of cam assembly 25 shown in the same figures.

Each stretcher has a plurality of laterally spaced clamps 33, and each clamp includes the opposed jaws 34 and 35 provided at their inner ends with co-operating arcuate gripping portions 36. The outer ends of the jaws are pivoted at 38 to the rod 37 for vertical movement of the jaws toward and away from each other. A compression 'coil spring 39 between the jaws of each clamp urges them apart to the open position illustrated at the right in FIGURE 3.

The clamps 33 are individually reciprocated in the direction of movement of the cam assemblies, indicated by arrows 26, by the hydraulic devices 40, each of which has a cylinder 41 rigidly secured to the base 24 and a piston (not shown) reciprocable therein. The rod 42 of each piston is connected to the rod 37 of each clamp by a coupling 43.

Each stretcher has an equal number of clamps, and the clamps of one stretcher are respectively directly opposite those of the other. The clamps 33 of both stretchers are all in their inner positions in FIGURES 2 and 3, that is the clamps of each stretcher are extended toward the other stretcher. Since the clamps of each stretcher are reciprocated by individual hydraulic devices 40 they can be reciprocated through different distances, that is the stroke of any one clamp can be different from that of the others. In the present instance, the outer positions of the clamps are different so that certain portions of the insulator can be stretched more than other portions. In FIGURE 2, the clamps are shown retracted in dotted lines just before they release the insulator.

The jaws of each clamp carry cam followers is the form of rollers 44 which respectively travel in contoured grooves 45 of the upper and lower plates 27 and 28. Each groove 45 has an intermediate straight horizontal portion 46 and vertically offset terminal portions 47 and 48. The grooves in the upper and lower cams for the followers of the same clamp are vertically opposed and are mirror images of each other in size and contour, and their intermediate portions 46 are parallel. The intermediate portions of the cam grooves force the jaws of the clamps together into gripping relation, as seen at the left in FIG- URE 3, and the offset end portions 47 and 48 enable the jaws of the respective clamps to open, as seen at the right in FIGURE 3, under the influence of the springs 39. The lengths of the intermediate portions of the grooves for the various clamps depends upon the strokes of the clamps, as will be understood from a comparison of the grooves for the two clamps shown in FIGURE 3.

In the operation of the stretching apparatus, it will be assumed that both cam assemblies 25 and 25 are in the outer position shown at the right of FIGURE 3, that is in positions retracted away from each other, and that the clamps 33 of each stretcher are in their inner positions so that the jaws thereof are open. An insulator A will then be positioned between the two stretchers 22 and 23 and the hydraulic devices 30 operated to move the cam assemblies 25 and 25' toward each other to their inner positions, seen at the left in FIGURE 3, closing the jaws of each clamp and thereby causing the anchorage portions 13 along both ends of the insulator to be gripped by the gripping portions 36 of the jaws. The hydraulic devices 40 are then operated to move the clamps of the two stretchers 22 and 23 away from each other to their outer positions. The clamps are shown in dotted lines in FIGURE 2 as they approach their outer positions and just prior to the release of the anchorage portions 13. The hydraulic devices 40 will of course be adjusted so that each clamp will retract the exact distance necessary to stretch the insulator to the desired configuration. In this connection, it will be understood that the intermediate portions 46 of the opposed cam grooves in the upper and lower cam plates 27 and 28 for each clamp will be somewhat shorter than the stroke of that clamp so that the clamp will remain closed during most of its outward movement (to the point indicated in dotted lines in FIG- URE 2) and will open only at the very end of its outward movement. Hence when the clamps reach their Outer or retracted positions, they automatically open and re= lease the insulator.

If desired, the hydraulic devices 40 can be controlled to dwell near their outer positions (the positions shown in dotted lines in FIGURE 2), momentarily holding the insulator in a stretched condition, and thereafter to complete their strokes causing the cam followers to drop into the offset groove portions 47, opening the clamps and releasing the insulator. The hydraulic devices 40 are simultaneously operated to retract the respective clamps at the same time, and the stroke of each clamp of one stretcher is equal to the stroke of the opposing clamp of the other stretcher.

After the clamps 33 have been retracted by the hydraulic devices 40, the hydraulic devices 30 are operated to move the cam assemblies 25 and 25' of each stretcher away from each other to their outer positions, and the hydraulic devices 40 are operated to move the clamps 33 to their inner positions, so that the positions of the parts of both stretchers are as shown at the right in FIGURE 3. The apparatus is now ready to stretch another insulator.

Referring to FIGURE 2, it will be seen that the insulator is stretched lengthwise to a contour substantially the same as that of the border frame 18 of the supporting spring structure, although preferably it is overstretched somewhat as shown in FIGURE 2 so that upon release of the insulator the inherent springback will cause the insulator to assume a stable prestretched condition substantially conforming to the border frame in configuration and in overall length. Instead of being overstretched, the insulator may alternatively be stretched substantially to the configuration and overall length of the border frame. When released by the stretching apparatus, it will spring back somewhat to a length slightly less than that of the border frame although its ends will be of the same configuration as the ends of the border frame. In either case, the reinforcing strands of the insulator are stretched beyond their initial elastic limit and accordingly assume a stable pre-stretched condition.

Although the various elements of my insulator may be formed of any suitable material for the purposes set forth, the rectangular sheet 10 is preferably formed of burlap, and the reinforcing strands 11 are preferably formed of wire of circular cross-section. The anchorage portions 13 are preferably formed of rolled or folded burlap.

The pre-stretched insulator is shown in FIGURE 4 secured to the border frame 18. The pro-stretched insulator may have the configuration and length of the border frame, in which event it would be in a free state condition when secured to the border frame as shown in FIGURE 4. On the other hand, the pre-stretched insulator may in its free state by slightly shorter than, although of the same configuration as, the border frame, in which event the pre-stretched insulator in FIGURE 4 would be in longitudinal tension, having been stretched somewhat beyond its stable pre-stretched condition when attached to the border frame.

In order to apply the insulator A to the border frame 18 of the supporting spring structure, one end of the insulator is attached to one end 20 or 21 of the border frame by hog rings 49. The hog rings 49 embrace both the anchorage portion 13 and the border frame at the end of the supporting spring structure.

capable of being deformed to cross or open'the ends to secure the anchorage portion 13 of the insulator to or release it from the borderfframeL The configuration of the hog rings is clearly shown in FIGURES 14. and

illustrating a modification described more fully hereinafter. The opposite end of theinsulator is then secured .to the opposite end of the border frame by hog rings 49 in the same manner. If the insulator, by reason of springback, is somewhat shorter than the border frame in its stable pro-stretched condition, it must of course be horizontally stretched before its opposite end is secured to the opposite end of the border frame.

Either before or after the ends of the insulator are secured by hog rings, as described above, the longitudinal edges of the insulator will be secured to the parallel sides and 51 of the border frame 18 by additional spaced hog rings 49. The hog rings 49 along the longitudinal edges of the insulator pierce the body of the sheet Ill and encircle the sides 50 and 51 of the border frame.

After the pre-stretched insulator is secured to the border frame, both the pleated fabric and reinforcing strands thereof remain in an undulated condition. 7 Referring to FIGURES 4 and 11', the sheet and reinforcing strands will be seen to be stretched considerably along side 5d of the border frame. However, along the opposite side 51 of the border frame, the pleated fabric and the reinforcing strands are extended very little if at all '(FIG- URES 4 and 5)., Hence in this section of the insulator, the pleats or undulations in the fabric are deep and the strands are more closely coiled. Between the opposite Y longitudinal edges of the insulator, the fabric and reinforcing strands are stretched to varying degrees, as will be apparent from an inspection of FIGURES 4 and 6l1.

It will be observed that both the fabricsheet and the reinforcing strands remain in an undulated condition after application to the border frame of the supporting spring structure at all points, although at some points the undulations are deeper or more closely formed than at others. Hence, the insulator, when applied to the supporting spring structure as shown in FIGURE 4, remains stretchable at all points to compensate for localized loads imposed thereon.

Referring to FIGURES 12-15, the insulator A there shown is a pre-stretched insulator having the same width as the border frame, as was the case in FIGURES 1-11. The insulator is shown in its stable free state condition and will be seen to have an overall length greater than that of the border frame, although the contour of its ends is the same as the contour of the border frame ends. Applied over the insulator A and bonded thereto in surface to-surface relation by any suitable adhesive is a layer 54 of cotton or any like soft cushion material, the layer of cotton having substantially the same configuration as the pro-stretched insulatorA although it is somewhat longer and wider. The insulator A and layer 54- bonded thereto are shown in FIGURE 12 overlying the border frame 18 prior to being secured thereto. 1

FIGURES 13-15 illustrate the insulator A and layer 54 bonded thereto after they have been secured by hog rings 4-9 to the border frame. As seen in FIGURE 14, hog rings 49 along the sides of the border frame embrace the border frame and pierce the material of the insulator fabric and of the layer 54 to firmly attach the marginal portions of the insulator and layer to the border frame.

Hog rings 49 also secure the ends of the insulator A and layer 54 to the ends 2% and 21 of the border frame.

seen in FIGURE 15, the ends of the insulator A and layer g folded portions thereof, to firmly border frame. A V V It will be understood't'hat the layer 54 of cotton or like materialis first bonded in surface-to-surface relation to the pro-stretched insulator A, and-theassembly composed attach the same tothe frame by the hog rings. s What I claimas myinvention is:

of the insulator and layer'is then Zsecuredto the border n l. A method of forming an elongated, flexible, sheet like insulator having in its free state condition a length- Wise dimension approximating the lengthwise dimension of an elongated border frame ofasupporting spring structure of an upholstered assembly, for'useof said insulator in said upholstered assembly between said supporting spring structure and an overlying padding; comprising providing a preformed, elongated, flexible, stretchable, resilient sheet-like insulator having an initial lengthwise dimension in its free state less than the minimum lengthwise dimension of said border frame, and longitudinally stretching said preformed insulator beyond its elastic limit to a stable free state condition of increased length in which the lengthwise dimension thereof approximates the lengthwise dimension of said border frame.

2. The method defined in claim 1, wherein said preformed insulator is longitudinally stretched as aforesaid end portions is gripped as aforesaid at laterally spaced points which are opposed to the points at which the other end portion is gripped.

5. A method offorming an elongated flexible, sheetlike insulator having in its free state condition a lengthwise dimension approximating the lengthwise dimension of an elongated border frameof a supporting spring structure of an upholstered assembly, for use of'said insulator in said upholstered assembly between said supporting spring structure and an overlying padding; comprising providing a preformed insulator including an elongated rectangular sheet of flexible material provided with transverse undulations and having an initial lengthwise dimension less than the lengthwise dimension of 'said border a frame, and also including a plurality of elongated, laterally spaced, substantially parallel, stretchable, resilientreinforcing strands threaded through said undulations and extending longitudinally of said sheet, and longitudinally stretching said preformed insulator to a free state condition of increased length in which the lengthwise dimension of said strands and of said sheet approximates the and then releasing the same.

7. The method defined in claim 6, wherein said preformed insulator is longitudinally stretched as aforesaid to a stable free state condition in which the ends of said sheet and said anchorage members conform substantially in contour to the ends of said border frame. r r

8. The method defined in claim 6, wherein said pre r formed insulator is overstretched by the aforesaid mcivement away from each other of said gripped anchorage members so that when released said insulator Will spring backto a lengthwise dimension more nearly approximating the lengthwise dimension of said border frame" 9. The method defined in claim 6, wherein said anchoragemembers are gripped as aforesaid for a predetermined interval of time following movement thereof away from each other and prior to release of the same.

10. The method defined in claim 6, including the further step of attaching said anchorage members to said ends of the border frame after said insulator has been longitudinally stretched as aforesaid.

11. The method defined in claim 6, including bonding References Cited by the Examiner UNITED STATES PATENTS 2,058,165 10/36 McCoy Q. 29173 1 2,218,708 10/40 Habersturnp 155179 2,283,116 5/42 Young 155-179 2,949,667 8/60 Cameron et a1. 29-452 X WHITMORE A. WlLTZ, Primary Examiner.

THOMAS H. EAGER, Examiner. 

1. A METHOD OF FORMING AN ELONGATED, FLEXIBLE, SHEETLIKE INSULATOR HAVING IN ITS FREE STATE CONDITION A LENGTHWISE DIMENSION APPROXIMATING THE LENGTHWISE DIMENSION OF AN ELONGATED BORDER FRAME OF A SUPPORTING SPRING STRUCTURE OF AN UPHOLSTERED ASSEMBLY, FOR USE OF SAID INSULATOR IN SAID UPHOLSTERED ASSEMBLY BETWEEN SAID SUPPORTING SPRING STRUCTURE AND AN OVERLYING PADDING; COMPRISING PROVIDING A PREFORMED, ELONGATED, FLEXIBLE, STRETCHABLE, RESILIENT SHEET-LIKE INSULATOR HAVING AN INITIAL LENGTHWISE DIMENSION IN ITS FREE STATE LESS THAN THE MINIMUM LENGTHWISE DIMENSION OF SAID BORDER FRAME, AND LONGITUDINALLY STRETCHING SAID PERFORMED INSULATOR BEYOND ITS ELASTIC LIMIT TO A STABLE FREE STATE CONDITION OF INCREASES LENGTH IN WHICH THE LENGTHWISE DIMENSION THEREOF APPROXIMATES THE LENGTHWISE DIMENSION OF SAID BORDER FRAME. 